<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>CssHue实现背景渐变</title>
    <style>
      body {
        margin: 0;
      }

      .intro {
        background: url('https://newevolutiondesigns.com/images/freebies/cool-wallpaper-3.jpg'),
          linear-gradient(233deg, #e56420, #c22525, #3d9c31, #37bbde);
        width: 100%;
        height: 100vh;
        background-size: cover;
        background-blend-mode: hard-light;
        animation: hue-rotate 3s linear infinite;
      }

      @keyframes hue-rotate {
        from {
          -webkit-filter: hue-rotate(0);
          -moz-filter: hue-rotate(0);
          -ms-filter: hue-rotate(0);
          filter: hue-rotate(0);
        }
        to {
          -webkit-filter: hue-rotate(360deg);
          -moz-filter: hue-rotate(360deg);
          -ms-filter: hue-rotate(360deg);
          filter: hue-rotate(360deg);
        }
      }
    </style>
  </head>
  <body>
    <div class="intro"></div>
  </body>
</html>
